Density scaling relation in Orion A: effects of region selection

TL;DR

This paper investigates how the choice of regions affects the derived density scaling relations in Orion A, revealing gravity's significant role in the cloud's energy balance through analysis of Planck dust-opacity data.

Contribution

It applies a density scaling relation method to Orion A and demonstrates the influence of region selection on the results, highlighting gravity's importance.

Findings

Steep density scaling relation with index -1.6 in the Central filament

Gravity plays a major role in the energy balance of Orion A

Results are consistent across different parts of the cloud

Abstract

Recently Stanchev et al. (2015) proposed a technique to derive density scaling relations in a star-forming region from analysis of the probability distribution function of column density. We address the possible dependence of the outcome on the selection of probe zones, applying the method to Planck dust-opacity data on Orion A. The derived steep scaling relation of mean density with index -1.6 in the molecular cloud (so called `Central filament') points to its self-gravitating nature. The result is reproduced also for large parts of the clouds' vicinity which indicates major role of gravity in the energy balance of the entire star-forming region.